Rotating grate for gas producers



Oct. 1, 1957 G. JUNKERS ROTATING GRATE FOR GAS PRODUCERS Filed June 16,1955 REGULATOR AUXILLIA RY STEAM SUPPLY PURE OXYGEN O12 OXYGEN .ENRICHED AIR.

MAIN AIR AND STEAM SUPPLY INVENTORQ JUNKdES.

United States Patent 7' ROTATING GRATE FOR GAS PRODUCERS Gerd Junkers,Essen, Germany, assignor, by mesne assignments, to Koppers Company,Inc., Pittsburgh, Pa, a corporation of Delaware Application June 16,1955, Serial No. 516,015

5 Claims. (Cl. 48-66) This invention relates to improvements in arotating grate for gas producers and has for its object the provision ofan improved grate construction for such a producer, such grateconstruction facilitating the maintenance of a uniform ash layer abovethe grate.

As is known, rotating grate gas producers are so constructed andoperated that a layer of ash is maintained above the grate to protectthe latter from the reaction temperature within the producer shaft, thethickness of said ash layer being controlled by the rotational speed ofthe grate and the position of one or more strippers arranged adjacent tothe grate and adapted to strip the ash from the grate and direct it toan ash pit. The thickness of the ash layer under any particular workingconditions may be adjusted by adjustment of the said rotational speed ofthe grate and/or by adjustment of the said stripper or strippers; it isknown to utilize temperature-sensitive mechanisms adjacent to the grateas a means for detecting the thickness of the ash layer and to causeappropriate adjustments to be made to maintain a predetermined ash layerthickness on the grate.

When there are large and frequent changes in the gas demand upon theproducer, or when the latter contains a charge of non-uniform particlesize and/or water and ash content, an ash layer of irregular depth mayeasily be formed upon the grate, this leading to non-uniformity in thedistribution of the gasification medium throughout the charge and inconsequence inefficient gas produc tion. The restoration of a uniformash layer upon the grate cannot readily be achieved.

These difiiculties in the operation of gas producers arise whatever thegasification medium employed, viz. air, steam or an air/steam mixture,but are particularly apparent when the gasification medium is oxygen oroxygen-enriched air, or a mixture of steam with oxygen oroxygen-enriched air, the difficulties being dependent upon the oxygencontent of the gasification medium.

It will be appreciated that so long as there is a uniform layer of ashover the grate, the resistance to flow of the gasification mediumthrough the grate and into the producer shaft will be uniform over thewhole area of the grate. However, When the ash layer becomes nonuniform,the resistance to the gasification medium flow through the grate willdecrease in those areas in which the ash layer is of the least thicknessso that the gasification medium preferentially flows through the gratein the areas of least ash layer thickness, and may, by increasing therate of reaction in the charge above such areas, cause damage to thegrate in these areas through the generation of excessive temperatures.

With the object of minimising this effect of the ash layer thicknessupon the gasification medium distribution, it has been proposed toprovide the underside of the grate with compartments of sector form toserve as distribution chambers for the gasification medium, gasificationmedium being supplied to all these chambers at a uniform pressure sothat the tendency for the gasification medium to migrate across theunderside of the grate to those 2,808,321 Patented Oct. 1, 1957' ICCareas ofthe latter carrying'the least thickness of ash layer isminimized.

In accordance, with the present invention, I provide, in or for arotating grate gas producer, a grate construction comprising a rotatinggrate provided on its underside with sector-shaped compartments and agasification medium supply conduit .beenath said grate and divided intocompartments corresponding with the grate compartments and communicatingwith the latter, said conduit compartments each being provided withmeans for regulating the flow of gasification medium therethrough.

With such an arrangement, the supply of gasification medium to the areasof the grate associated with the grate compartments can be independentlyregulated by adjustment of said flow-regulating means and in this waythe thickness of ash layer above each of said grate areas may becontrolled so that a uniform ash layer may be maintained over the wholearea of the grate. The control of the said flow-regulating means mayconveniently be effected automatically by means of temperature/sensitivemechanisms associated with the areas of the grate corresponding with thecompartments thereunder.

In accordance with a further feature of the invention, auxiliaryconduits may communicate with the said conduit compartments above thesaid flow-regulating means, these auxiliary conduits being adapted forthe admission of oxygen, oxygen-enriched air, and/ or steam to the saidconduit compartments to provide for finer control of the ash layerthickness upon the grate.

Thus when the ash layer above a particular area of the grate decreasesin thickness, steam may be admitted to the appropriate conduitcompartment so that the overall oxygen-content of the gasificationmedium supplied to said area of the grate is reduced, with a consequentreduction in the exothermic reaction rate in the charge above such areaof the grate. Conversely, when the ash layer above an area of the grateincreases beyond the desired thickness, oxygen or oxygen-enriched air,may be admitted to the appropriate conduit compartment so thatoxygen-enriched gasification medium flows through the said area of thegrate and counteracts the tendency of the thicker ash layer to slow downthe reaction rate in the charge above such area of the grate. Byappropriate adjustment of the amounts of steam and oxygen oroxygenenrlched air introduced into the conduit compartments through. thesaid auxiliary conduits, the reaction rate in the charge may bemaintained uniform over the whole cross-section of the producer shaftwith the result that a un form ash layer on the grate will be achieved.

Conveniently, the said temperature-sensitive mechamsms may control theadmission of oxygen, oxygen-enriched an, and steam to the said auxiliaryconduits and hence to the said conduit compartments.

Desirably, the conduit compartments communicate with the compartmentsbeneath the grate through radially extending apertures thereby toenhance the uniformity of distribution of gasification medium Within thegrate compartments.

A preferred embodiment of the invention is illustrated in theacompanying drawings in which:

Figure 1 is a vertical cross-section through the lower part of arotating grate gas producer equipped with a grate construction inaccordance with the present invention; I

Figure 2 is a horizontal section on the line IIII of Figure l; and IFigure 3 is a vertical section on the line III-III of Figure 2 Y The gasproducer illustrated in the drawings comprises a shaft 1 defined by adouble-walled jacket 2 in which hot water is circulated for coolingpurposesithe lower end of the jacket 2 being furnished with a dependentsealing ring 3 which dips under the surface of water contained within anannular ash pit 4.

The bottomof the ash pit 4 is constituted by a horizontal annulus 5 uponwhich is mounted a grate cornprising a lower portion 6 and an upperportion 7, the assembly comprising the ash pit and grate being rotatedabout its vertical axis by means of a worm-Wheel 8 meshing with atoothed ring 9 carried by the annulus 5.

The annulus 5 of the ash pit is mounted on a dependent crown 10 whichruns on rollers 11 arranged in a circle on the producer foundation 12.Ash collecting in the ash pit 4 is discharged over the outer rimthereof, whilst the ash pit is rotating, by means of an ash levellingdevice (not shown).

Gasification medium (usually a mixture of steam and air) is introducedinto the producer via a conduit 13 which passes through the producerfoundation 12 and communicates with the interior of the grate. Theannulus 5 carries a dependent sleeve 15 which dips under the surface ofwater contained in a cup 14 surrounding the conduit 13 so that agas-tight seal is formed between the conduit 13 and the interior of thegrate.

The upper and lower portions of the rotating grate are divided intosector-shaped compartments 16, as clearly shown in Figure 2. The walls17 of the compartments 16 extend downwardly to meet the annulus 5 uponwhich the grate is mounted. The walls 17 of the said compartments arepreferably formed with flanged extensions 29 which are connected to theadjacent Walls 17, for example by screws. The grate is convenientlyformed of cast steel and the upper portion 7 of the grate is of conicalform and is furnished with openings 27 through which the gasificationmedium may pass from the compartments 16 into the producer shaft 1.

The upper part of the conduit 13 is also divided into sector-shapedcompartments 28 corresponding to the compartments 16 of the grate; thecompartments 28 extend upwardly adjacent to the lower edges of the innermargins of the walls 17 of the compartments 16 so that gasificationmedium flowing up a conduit compartment 28 is directed to the gratecompartment 16 which at that instant lies above the compartment 28. Thefact that the walls 17 of the compartments 16 move out of registrationwith the walls of the conduit compartments 28 during rotation of thegrate is not detrimental to the gasification medium flow controlprovided by the grate construction of this invention, since when suchlack of registration occurs, the gasification medium flowing up oneconduit compartment 28 is divided between two compartments 16 of thegrate so that the gasification medium is still directed substantially tothe grate area desired.

Each conduit compartment 28 is furnished at its lower end with means forregulating the flow of gasification medium into such compartment fromthe undivided portion of the conduit 13, these means convenientlycomprising, as shown, a throttle valve 18 which is pivoted at 1-9 andoperable from the exterior of the conduit by means of a rod 20; byadjustment of the various rods 20, the distribution of the gasificationmedium amongst the conduit compartments 28 can readily be controlled.

An auxiliary conduit 21 communicates with each con duit compartment 28above the throttle valve 18 therein; each auxiliary conduit 21 isprovided with a steamadmission valve 22, whilst between the valve 22 andthe conduit compartment 28 a further conduit 23 is connected to theconduit 21 and is supplied with oxygen or oxygen-enriched air via avalve 24. By means of the valves 22 and 24, the conduit compartments 28can be selectively supplied with additional steam or oxygen inappropriate quantities for controlling the ash layer thickness above thecorresponding area of the grate.

In operation of the producer above described, the flow of gasificationmedium to different areas of the grate will be controlled by adjustmentof the throttle valves 18; where such adjustment is ineffective tomaintain uniformity of the ash layer thickness above the grate, steamwill be admitted to those conduit compartments 28 which correspond tothe various areas of the grate upon which the ash layer has become toothin, whilst oxygen or oxygen-enriched air will be admitted to thoseconduit compartments 28 corresponding to areas of the grate carrying anexcessive thickness of ash layer.

The adjustment of the throttle valves 18 and the valves 22 and 24 of theauxiliary conduits 21 may be effected manually or automatially.Automatic regulation may be achieved by the use of temperature-sensitivemechanisms which may be located on the grate itself (such as shown at 26in Figure l) or within the shaft 1 just above the grate; thetemperature-sensitive mechanisms would of course be associated withappropriate control means (not shown in the drawings) connected to thesaid throttle valves 18 and valves 22 and 24.

The conduit compartments 28 may have any suitable cross-section,although a sector-shaped cross-section corresponding to thecross-section of the grate compartments 16 is preferred; the upper endsof the conduit compartments 28 preferably terminate in radiallyextending apertures 30 (see Figure 3), which act as nozzles directingthe gasification medium into the appropriate compartments 16 of thegrate.

If desired, the compartments 16 of the grate and also the conduitcompartments 28, may be further subdivided by appropriate walls toenable the distribution of gasification medium to radially spaced areasof the grate to be controlled.

What I claim is:

1. In a rotating grate gas producer, a gas producer shaft with arotating grate, sector shaped vertical compartments arranged around theaxis of rotation of the grate on the underside thereof and integrallywith the grate, a stationary gasification medium supply conduit beneaththe compartments of the grade and coaxial therewith, said conduit beingsubdivided into a coaxial series of stationary vertical compartmentscorresponding with rotatable compartments of the grate above andcommunicating at their upper parts with the lower parts of the gratecompartments during rotation of the grate, individually adjustable meansfor individually regulating the flow of gasification medium through therespective compartments of the supply conduit, and means for feeding themain steam and air supply for the producer bed in common to the supplyconduit compartments at their lower parts.

2. In a rotating grate gas producer, a gas producer shaft with arotating grate, sector shaped vertical compartments arranged around theaxis of rotation of the grate on the underside thereof and integrallywith the grate, a stationary gasification medium supply conduit beneaththe compartments of the grate and coaxial therewith, said conduit beingsubdivided into a coaxial series of stationary vertical compartments tocorrespond with rotatable compartments of the grate above andcommunicating at their upper parts with the lower parts of the gratecompartments during rotation of the grate, individually adjustable meansfor individually regulating the flow of gasification medium through therespective compartments of the supply conduit, and auxiliary conduitsindividually connected to the compartments of the supply conduit forselective admission thereto of auxiliary oxygen, oxygen-enriched air,and steam.

3. In a rotating grate gas producer, a gas producer shaft with arotating grate, sector shaped vertical compartments arranged around theaxis of rotation of the grate on the underside thereof and integrallywith the grate, a stationary gasification medium supply conduit beneaththe compartments of the grate and coaxial therewith, said conduit beingsubdivided into a coaxial series of stationary vertical compartmentscorresponding with rotatable compartments of the grate above andcommunicating at their upper parts with the lower parts of the gratecompartments during rotation of the grate, individually adjustable meansfor individually regulating the flow of gasification medium through therespective compartments of the supply conduit, auxiliary conduitsindividually connected to the compartments of the supply conduit forselective admission thereto of auxiliary oxygen, oxygenenriched air, andsteam, and temperature-sensitive elements arranged in the producer shaftto detect variations in the ash layer thickness carried by the differentareas above the grate, said elements including means also associatedWith the aforesaid individually adjustable means for the correspondingcompartments of the supply conduit to adjust the same automatically.

4. In a rotating grate gas producer, a gas producer shaft with arotating grate, sector shaped vertical compartments arranged around theaxis of rotation of the grate on the underside thereof and integrallywith the grate, a station ary gasification medium supply conduit beneaththe compartments of the grate and coaxial therewith, said conduit beingsubdivided into a coaxial series of stationary vertical compartmentscorresponding with rotatable compartments of the grate above andcommunicating at their upper parts with the lower parts of the gratecompartments during rotation of the grate, individually adjustable meansfor individually regulating the flow of gasification medium through therespective compartments of the supply conduit, auxiliary conduitsindividually connected to the compartments of the supply conduit forselective admission thereto of auxiliary oxygen, oxygen-enriched air,and steam, and temperature-sensitive elements arranged in the producershaft to detect variations in the ash layer thickness carried by thediiferent areas above the grate, said elements including means alsoassociated with the aforesaid individually adjustable means for thecorresponding compartments of the supply conduit to adjust the sameautomatically, and also associated With the individual auxiliaryconduits for the corresponding compart ments of the supply conduit tocontrol the admission of air and steam to said supply conduitcompartments.

5. Apparatus as claimed in claim 4, and in which the supply conduitcompartments terminate at their upper ends in radially extending slitsfor directing the gasification medium into the rotating compartments inthe rotary grate above.

References Cited in the file of this patent UNITED STATES PATENTS169,947 Bolender Nov. 16, 1875 655,086 Hunter July 31, 1900 1,928,609Van Ackeren Sept. 26, 1933 2,056,060 Van Ackeren Sept. 29, 19362,108,764 Deringer Feb. 15, 1938 2,164,262 Wagner June 27, 1939

1. IN A ROTATING GRATE GAS PRODUCER, A GAS PRODUCER SHAFT WITH AROTATING GRATE, SECTOR SHAPED VERTICAL COMPARTMENTS ARRANGED AROUND THEAXIS OF ROTATION OF THE GRATE ON THE UNDERSIDE THEREOF AND INTGRALLYWITH THE GRATE, A STATIONARY GASIFICATION MEDIUM SUPPLY CONDUIT BENEATHTHE COMPARTMENTS OF THE GRADE AND COAXIAL THEREWITH, SAID CONDUIT BEINGSUBDIVIDED INTO A COAXIAL SERIES OF STATIONARY VERTICAL COMPARTMENTCORRESPONDING WITH ROTATABLE COMPARTMENTS OF THE GRATE ABOVE ANDCOMMUNICATING AT THEIR UPPER PARTS WITH THE LOWER PARTS OF THE GRATECOMPARTMENTS DURING ROTATION OF THE GRATE, INDIVIDUALLY ADJUSTABLE MEANSFOR INDIVIDUALLY REGULATING THE FLOW OF GASIFICATION MEDIUM THROUGH THERESPECTIVE COMPARTMENTS OF THE SUPPLY CONDUIT, AND MEANS FOR FEEDING THEMAIN STEAM AND AIR SUPPLY FOR THE PRODUCER BED IN COMMON TO THE SUPPLYCONDUIT COMPARTMENTS AT THEIR LOWER PARTS.